AutoBan is an anti-junk plugin for use with the Apache webserver. It updates a .htaccess file to ban the IP addresses of junk sources. The list is generated from the junk objects stored in MT, providing for automatic aging. The updating is completely automatic.
AutoBan is primarily useful for preventing flooding attacks. It also turns out that many junkers rent the same zombies, so even new types of attacks that get past the filters tend to be moderate because old attacks get the sources banned.
Version 1.2.3 may not work in MT 4. Use the beta 1.2.4 release instead.